SLIDESHOW: Busy Beavers Gnaw Tree in Austin, Minn.

A viewer sent photos of a tree on Main Street. Beaver damage is not uncommon in the area. However, it's unusual that the beavers decided to gnaw on an ash tree.

Larry Dolphin with Hormel Nature Center said, "Their teeth are continually growing, so sometimes they pick on a harder tree... just to wear down their teeth, and you'll see that on some oaks and ash is a hardwood tree."

Beavers normally gnaw through smaller trees and softer, more nutritious wood like aspen and willow.